If you are tasting more than one wine, then before even starting you need to line the bottles up in the right order. Most important is to put the sweetest last, because once you've had anything sweet the dry wines will taste wretched - tannic, unpleasant and devoid of pleasure (for the same reason, don't eat anything sugary immediately before tasting).

Next, think about the intensity. Lighter-bodied wines should go towards the beginning of the line-up, as trying a basic Bordeaux, say, after a thumping great Barossa shiraz would be like attempting to hold a conversation on a mobile at a rock concert. Older vintages should follow younger ones because the wines will, or ought to, be more complex, and if you taste them first the young wines may seem dull and one-dimensional.

Finally, reds first or whites? Actually, it doesn't matter. It's traditional to do whites first, but I always taste the other way round. Reds require more concentration and I like to get them out of the way while I'm still focused. The whites are usually acidic enough to refresh your palate after all the tannin.

Pouring the wine

Use glasses that taper in slightly towards the rim. Professionals have their favourites: Riedel's Vinum Chianti glass, Dartington Crystal Chef's Taster glass and the ISO tasting glasses are all popular, but a set of Habitat tulips is fine too. Don't fill them any more than a quarter of the way up; an inch or so is enough to taste.

The colour

Your professional taster will now be standing in a white-painted north-facing room, tilting his glass against a white surface to examine the gradations of colour at the rim of the liquid in natural light. Red wines begin life a more bluish shade of crimson or purple and fade through shades of ruby, garnet and brick to a yellow-toned tawny depending on the grape and their age. Whites, on the other hand, deepen as they grow older.

For blind tasters this is an important clue-gathering exercise. For buyers already armed with information about the wine, it can help determine how well it is ageing (unusually advanced colour development may indicate poor storage or low acidity, for example). For the home drinker, colour isn't so important, though do take note if a white wine is unexpectedly dark - this may be the first sign that it is oxidised (spoilt by over-exposure to oxygen either in production or in the bottle).

Transparency

Is the wine clear? If it's cloudy, and unless it's a niche, artisan wine, take it back. If it contains small, white crystals like a snowstorm, that's fine: these are just tartrates that have precipitated out and they are harmless.

The swirl

Oh how show-offs love to swirl the wine and make knowing comments about its legs. But no one actually does this when tasting properly. The swirl is useful, though, as it helps release more of the volatile compounds, which intensifies the smell (there's really no need to call it "bouquet", which always makes me think of a bunch of flowers).

The nose

Take a good sniff. Tasters often talk about "primary aromas" in a young wine. These are the ones that remind you of fresh fruit. More mature wines develop complex smells that tend to be more vegetal and may remind you of mulching leaves or mushrooms. It's at this point that you might spot a fault in the wine, such as an excess of sulphur compounds, which you may pick up as smelling like burnt rubber, the sulphury part of the smell of a just-struck match, or murky cabbage-water.

The most common fault is cork taint, and the first indication that your wine is corked is usually an absence - a lack of "winey" smell or expressiveness. If the fault is severe, it will smell actively horrible - like soggy cardboard or damp - and you will pick the same problems up when you taste.

Making notes

Don't worry about how other people describe wine. Use your own vocabulary and stick to observations that will help you remember what you actually thought. It's easy to get carried away, but in my notes the highest - and most telling - terms of praise are "smells like Sancerre" (though only, obviously, if it is a Sancerre) and "alive".

Finally, it's in your mouth

Take a sip - enough to shuck round your mouth and not so much that your mouth is full. Suck in some air too and swish the liquid over your gums (which are sensitive to tannin, which feels drying, like tea), your tongue (you can pick up sweetness on the tip) and all round. As well as tannin and sweetness you will also notice acidity and alcohol, which confusingly also tastes sweet as well as adding heat and gloss. Professional tasters are taught to note all these individually, but more important is the big picture, and overall balance. All good wines should be balanced in their way - that is, there should be no sense of excess, or a feeling of the wine being out of kilter. It might be very acidic or very tannic or whatever, but it should still feel just so. It's if something sticks out - uncomfortable acidity or bitterness on the finish, or oak that overwhelms and shuts down the wine - that you should pay it attention.

Try to relax

One of the tricky things about deliberate tasting is that suddenly switching on your brain can change the emphasis of how a wine appears to taste. For example, I've noticed many people seem more sensitive to tannins when consciously tasting, and will say they prefer less tannic wines. Yet when they stop thinking and start drinking, a more "difficult" tannic wine is what they go for. So try to keep your instinctive response to the fore.

Now spit

They tell you to practise in the bath, but after years of wine tasting, I am still a hopeless spitter. Nonetheless, it is important to spit if you aim to taste more than three wines. After spitting, note how long the taste of the wine lingers in your mouth. This is called "the finish". A wine that's "short" disappears very suddenly. These are the sort of wines certain bars like to put on their list, because as soon as the taste fades you take another gulp and, before you know it, are ordering a second bottle. A "long" finish is a good thing.

A trick to ease nose fatigue

Professionals can taste hundreds of wines a day. Amateurs usually begin to flag after six, but you can revive your sense of smell by sniffing yourself. Yes, I know it sounds dodgy, but bury your nose in your arm or a scarf you have been wearing, inhale what for you will be a neutral smell, and you can reset your nose so that it's good for another wine at least.

Top 20 tasting terms

Austere Lean, hard, not ready to drink, but may improve with age. Such a wine may also be described as backward - the opposite of forward!

Beefy Solid stuff. (Only reds are ever beefy.)

Body A wine with plenty of flavour, alcohol, extract and tannin may be described as full-bodied.

Clean Tastes pure and innocent.

Coarse Lacks elegance.

Complex No inferiority complexes here - this is a quality that the best wines boast. Lots going on.

Elegant Delicious and well balanced.

Finesse Very elegant.

Forward Mature for its age.

Hard With overwhelming tannin or acidity.

Hollow Lacks flavour and texture.

Hot Some like it like this: very high in alcohol.

Integrated Good in business, good in wine: a wine is integrated when its components - such as tannin, oak and acidity - unite as it develops, so that no one element dominates.

Jammy Intensely ripe, concentrated fruit.

Mousse How fizzy a sparkling wine seems in the mouth. A soft mousse is not too fizzy. A harsh mousse is too fizzy.

Steely A high-acid, firm white wine, often a young one that may soften with age.

Supple Silky, smooth, no awkward edges.

Toasty Smells or tastes of - yes, you guessed it - toast. This may reflect "toasting" of the barrels over a fire as they are made.